It is known to use a copolymer of an organopolysiloxane and a radical-polymerizable monomer as a cosmetic raw material. For example, Japanese Laid-Open Patent Application Kokai No. 5-924 suggests using a vinyl polymer obtained by polymerizing a dimethylpolysiloxane oligomer that contains methacrylic groups with tertiary butyl acrylate and methacrylic acid as a base oil for a hair conditioner. Japanese Laid-Open Patent Application Kokai No. 9-59132 discloses a hair cosmetic material which contains an alternating block copolymer of a polydimethylsiloxane and a polyoxyalkylene. Furthermore, Japanese Laid-Open Patent Application Kokai No. 9-208,422 discloses a cosmetic composition which contains an emulsion obtained by polymerizing an organopolysiloxane with butyl acrylate, methacrylic acid, styrene, and acrylic acid. However, these cosmetic raw materials have poor affinity to other cosmetic raw materials and show unsatisfactory compounding stability with respect to cosmetic products. While these cosmetic raw materials impart hydrophobic properties and smoothness to cosmetic products, they impair adhesion to hair and skin, can be easily removed from hair and skin, and impair surface-protective properties.